RNA-seq analyses on gametogenic tissues of alfalfa (Medicago sativa) revealed plant reproduction- and ploidy-related genes.

BACKGROUND: In alfalfa (Medicago sativa), the coexistence of interfertile subspecies (i.e. sativa, falcata and coerulea) characterized by different ploidy levels (diploidy and tetraploidy) and the occurrence of meiotic mutants capable of producing unreduced (2n) gametes, have been efficiently combined for the establishment of new polyploids. The wealth of agronomic data concerning forage quality and yield provides a thorough insight into the practical benefits of polyploidization. However, many of the underlying molecular mechanisms regarding gene expression and regulation remained completely unexplored. In this study, we aimed to address this gap by examining the transcriptome profiles of leaves and reproductive tissues, corresponding to anthers and pistils, sampled at different time points from diploid and tetraploid Medicago sativa individuals belonging to progenies produced by bilateral sexual polyploidization (dBSP and tBSP, respectively) and tetraploid individuals stemmed from unilateral sexual polyploidization (tUSP). RESULTS: Considering the crucial role played by anthers and pistils in the reduced and unreduced gametes formation, we firstly analyzed the transcriptional profiles of the reproductive tissues at different stages, regardless of the ploidy level and the origin of the samples. By using and combining three different analytical methodologies, namely weighted-gene co-expression network analysis (WGCNA), tau (τ) analysis, and differentially expressed genes (DEGs) analysis, we identified a robust set of genes and transcription factors potentially involved in both male sporogenesis and gametogenesis processes, particularly in crossing-over, callose synthesis, and exine formation. Subsequently, we assessed at the same floral stage, the differences attributable to the ploidy level (tBSP vs. dBSP) or the origin (tBSP vs. tUSP) of the samples, leading to the identification of ploidy and parent-specific genes. In this way, we identified, for example, genes that are specifically upregulated and downregulated in flower buds in the comparison between tBSP and dBSP, which could explain the reduced fertility of the former compared to the latter materials. CONCLUSIONS: While this study primarily functions as an extensive investigation at the transcriptomic level, the data provided could represent not only a valuable original asset for the scientific community but also a fully exploitable genomic resource for functional analyses in alfalfa.

Generic Workflow of a Highly Effective and Easy Anther Culture Method for Both Japonica and Indica Rice.

As one of the most important staple crops in the world, rice plays a pivotal role in world food security. The creation of doubled haploids based on anther culture is an important technology for rice breeding. However, at present, rice anther culture technology still faces many problems, such as genotype dependency, especially genotypes of indica rice. In this study, fifteen rice genotypes, including twelve japonica rice genotypes and three indica rice genotypes, were randomly selected and used to study anther culture by using a modified M8 medium. The results showed that the total callus induction rates of these different rice genotypes ranged from 0.81 to 13.95%, with an average of 6.64%, while the callus induction rates calculated for the top ten highest callus inductions for each rice genotype ranged from 2.75 to 17.00%, with an average of 10.56%. There were varying gaps between the total callus induction rates and the callus induction rates in these different rice genotypes. The fact that the gaps for some rice genotypes were relatively large indicated that standard tiller or anther collection was not applicable to all rice genotypes and that there was still a lot of room for improvement in the callus induction rate of some rice genotypes through optimization of the sampling method. The plantlet regeneration rates ranged from 12.55 to 456.54%, with an average of 200.10%. Although there were many albinos from anther culture for some rice genotypes, these would still meet the requirement if the rice genotypes had higher callus induction rates or regeneration rates. The percentages of seed setting of regenerated green seedlings ranged from 14% to 84%, with an average of 48.73%. Genetic diversity analysis showed that the genetic background of these different rice genotypes was representative, and the phylogenetic tree and Principal Component Analysis (PCA) divided them into indica and japonica types. Therefore, in this study, an anther culture method suitable for both indica and japonica rice genotypes was established, which could improve doubled haploid breeding in rice.

Is the liver resilient to the process of ageing?

The liver's unique regenerative capacity, immunotolerant feature, and polyploidy status distinguish it as a metabolic organ unlike any other in the body. Despite aging, the liver generally exhibits fewer pathological abnormalities than other organs (such as the kidney), maintaining its functions near-normal balanced manner. Subtle changes in the liver, including reduced blood flow, detoxification alterations, pseudo-capillarization, and lipofuscin deposition, may occur with chronological age. Research indicates that carefully selected liver grafts from octogenarian donors can perform well post-transplant, emphasizing instances where age doesn't necessarily compromise liver function. Notably, a recent report suggests that the liver is a youthful organ, with hepatocytes averaging an age of only 3 years. Despite the liver's impressive regenerative capabilities and cellular reserve, a lingering question persists: how does the liver maintain its youthful characteristic amidst the chronological aging of the entire organism? The various adaptive mechanism possibly include:(a) cellular hypertrophy to maintain physiological capacity even before proliferation initiates, (b) the "ploidy conveyor" as a genetic adaptation to endure aging-related stress, (c) sustained telomere length indicative of youthfulness (d) active extracellular matrix remodelling for normal cellular functioning, (e) Mitochondria-Endoplasmic Reticulum based metabolic adaptation and (c) cellular plasticity as fitness mechanisms for healthy aging. However, it's crucial to note that aged livers may have compromised regenerative capacity and chronic liver disease is often associated with declining function due to premature hepatocyte senescence. This review delves into varied cellular adaptations sustaining liver homeostasis with chronological aging and briefly explores the role of accelerated hepatocyte aging as a precursor to chronic liver disease.

Testicular mosaicism in non-mosaic postpubertal Klinefelter patients with focal spermatogenesis and in non-mosaic prepubertal Klinefelter boys.

STUDY QUESTION: Do testis-specific cells have a normal karyotype in non-mosaic postpubertal Klinefelter syndrome (KS) patients with focal spermatogenesis and in non-mosaic prepubertal KS boys? SUMMARY ANSWER: Spermatogonia have a 46, XY karyotype, and Sertoli cells surrounding these spermatogonia in postpubertal patients also have a 46, XY karyotype, whereas, in prepubertal KS boys, Sertoli cells surrounding the spermatogonia still have a 47, XXY karyotype. WHAT IS KNOWN ALREADY: A significant proportion of patients with non-mosaic KS can have children by using assisted reproductive techniques thanks to focal spermatogenesis. However, the karyotype of the cells that are able to support focal spermatogenesis has not been revealed. STUDY DESIGN, SIZE, DURATION: Testicular biopsy samples from non-mosaic KS patients were included in the study. Karyotyping for sex chromosomes in testis-specific cells was performed by immunohistochemical analysis of inactive X (Xi) chromosome and/or fluorescent in situ hybridization (FISH) analysis of chromosomes 18, X, and Y. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 22 KS patients (17 postpubertal and 5 prepubertal) who were non-mosaic according to lymphocyte karyotype analysis, were included in the study. After tissue processing, paraffin embedding, and sectioning, the following primary antibodies were used for cell-specific analysis and Xi detection; one section was stained with MAGE A4 for spermatogonia, SOX9 for Sertoli cells, and H3K27me3 for Xi; the other one was stained with CYP17A1 for Leydig cells, ACTA2 for peritubular myoid cells, and H3K27me3 for Xi. Xi negative (Xi-) somatic cells (i.e. Sertoli cells, Leydig cells, and peritubular myoid cells) were evaluated as having the 46, XY karyotype; Xi positive (Xi+) somatic cells were evaluated as having the 47, XXY. FISH stain for chromosomes 18, X, and Y was performed on the same sections to investigate the karyotype of spermatogonia and to validate the immunohistochemistry results for somatic cells. MAIN RESULTS AND THE ROLE OF CHANCE: According to our data, all spermatogonia in both postpubertal and prepubertal non-mosaic KS patients seem to have 46, XY karyotype. However, while the Sertoli cells surrounding spermatogonia in postpubertal samples also had a 46, XY karyotype, the Sertoli cells surrounding spermatogonia in prepubertal samples had a 47, XXY karyotype. In addition, while the Sertoli cells in some of the Sertoli cell-only tubules had 46, XY karyotype, the Sertoli cells in some of the other Sertoli cell-only tubules had 47, XXY karyotype in postpubertal samples. In contrast to the postpubertal samples, Sertoli cells in all tubules in the prepubertal samples had the 47, XXY karyotype. Our data also suggest that germ cells lose the extra X chromosome during embryonic, fetal, or neonatal life, while Sertoli cells lose it around puberty. Peritubular myoid cells and Leydig cells may also be mosaic in both postpubertal patients and prepubertal boys, but it requires further investigation. LIMITATIONS, REASONS FOR CAUTION: The number of prepubertal testicle samples containing spermatogonia is limited, so more samples are needed for a definitive conclusion. The fact that not all the cell nuclei coincide with the section plane limits the accurate detection of X chromosomes by immunohistochemistry and FISH in some cells. To overcome this limitation, X chromosome analysis could be performed by different techniques on intact cells isolated from fresh tissue. Additionally, there is no evidence that X chromosome inactivation reoccurs after activation of the Xi during germ cell migration during embryogenesis, limiting the prediction of X chromosome content in germ cells by H3K27me3. WIDER IMPLICATIONS OF THE FINDINGS: Our findings will lay the groundwork for new clinically important studies on exactly when and by which mechanism an extra X chromosome is lost in spermatogonia and Sertoli cells. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by The Scientific and Technological Research Council of Türkiye (TUBITAK) (2219 - International Postdoctoral Research Fellowship Program for Turkish Citizens) and the Strategic Research Program (SRP89) from the Vrije Universiteit Brussel. The authors declare no competing interests. TRIAL REGISTRATION NUMBER: N/A.

Improving wine fermentation efficiency of Torulaspora delbrueckii by increasing the ploidy of yeast inocula.

The life cycle of most non-conventional yeasts, such as Torulaspora delbrueckii (Td), is not as well-understood as that of Saccharomyces cerevisiae (Sc). Td is generally assumed to be haploid, which detracts from some biotechnological properties compared to diploid Sc strains. We analyzed the life cycle of several Td wine strains and found that they were mainly diploid during exponential growth in rich medium. However, most cells became haploid in stationary phase, as observed for Sc haploid heterothallic strains. When transferred and incubated in nutrient-deficient media, these haploid cells became polymorphic, enlarged, and transitioned to diploid or polyploid states. The increased ploidy, that mainly results from supernumerary mitosis without cytokinesis, was followed by sporulation. A similar response was observed in yeasts that remained alive during the second fermentation of base wine for sparkling wine making, or during growth in ethanol-supplemented medium. This response was not observed in the Sc yeast populations under any of the experimental conditions assayed, which suggests that it is a specific adaptation of Td to the stressful fermentation conditions. This response allows Td yeasts to remain alive and metabolically active longer during wine fermentation. Consequently, we designed procedures to increase the cell size and ploidy of haploid Td strains. Td inocula with increased ploidy showed enhanced fermentation efficiency compared to haploid inocula of the same strains.

Exploration of inhibitors targeting KIF18A with ploidy-specific lethality.

Currently, various antimitotic inhibitors applied in tumor therapy. However, these inhibitors exhibit targeted toxicity to some extent. As a motor protein, kinesin family member 18A (KIF18A) is crucial to spindle formation and is associated with tumors exhibiting ploidy-specific characteristics such as chromosomal aneuploidy, whole-genome doubling (WGD), and chromosomal instability (CIN). Differing from traditional antimitotic targets, KIF18A exhibits tumor-specific selectivity. The functional loss or attenuation of KIF18A results in vulnerability of tumor cells with ploidy-specific characteristics, with lesser effects on diploid cells. Research on inhibitors targeting KIF18A with ploidy-specific lethality holds significant importance. This review provides a brief overview of the regulatory mechanisms of the ploidy-specific lethality target KIF18A and the research advancements in its inhibitors, aiming to facilitate the development of KIF18A inhibitors.

Improving Deep Learning-Based Algorithm for Ploidy Status Prediction Through Combined U-NET Blastocyst Segmentation and Sequential Time-Lapse Blastocysts Images.

Background: Several approaches have been proposed to optimize the construction of an artificial intelligence-based model for assessing ploidy status. These encompass the investigation of algorithms, refining image segmentation techniques, and discerning essential patterns throughout embryonic development. The purpose of the current study was to evaluate the effectiveness of using U-NET architecture for embryo segmentation and time-lapse embryo image sequence extraction, three and ten hr before biopsy to improve model accuracy for prediction of embryonic ploidy status. Methods: A total of 1.020 time-lapse videos of blastocysts with known ploidy status were used to construct a convolutional neural network (CNN)-based model for ploidy detection. Sequential images of each blastocyst were extracted from the time-lapse videos over a period of three and ten hr prior to the biopsy, generating 31.642 and 99.324 blastocyst images, respectively. U-NET architecture was applied for blastocyst image segmentation before its implementation in CNN-based model development. Results: The accuracy of ploidy prediction model without applying the U-NET segmented sequential embryo images was 0.59 and 0.63 over a period of three and ten hr before biopsy, respectively. Improved model accuracy of 0.61 and 0.66 was achieved, respectively with the implementation of U-NET architecture for embryo segmentation on the current model. Extracting blastocyst images over a 10 hr period yields higher accuracy compared to a three-hr extraction period prior to biopsy. Conclusion: Combined implementation of U-NET architecture for blastocyst image segmentation and the sequential compilation of ten hr of time-lapse blastocyst images could yield a CNN-based model with improved accuracy in predicting ploidy status.

Potato soup: analysis of cultivated potato gene bank populations reveals high diversity and little structure.

Cultivated potatoes are incredibly diverse, ranging from diploid to pentaploid and encompass four different species. They are adapted to disparate environments and conditions and carry unique alleles for resistance to pests and pathogens. Describing how diversity is partitioned within and among these populations is essential to understanding the potato genome and effectively utilizing landraces in breeding. This task is complicated by the difficulty of making comparisons across cytotypes and extensive admixture within section petota. We genotyped 730 accessions from the US Potato genebank including wild diploids and cultivated diploids and tetraploids using Genotype-by-sequencing. This data set allowed us to interrogate population structure and diversity as well as generate core subsets which will support breeders in efficiently screening genebank material for biotic and abiotic stress resistance alleles. We found that even controlling for ploidy, tetraploid material exhibited higher observed and expected heterozygosity than diploid accessions. In particular group chilotanum material was the most heterozygous and the only taxa not to exhibit any inbreeding. This may in part be because group chilotanum has a history of introgression not just from wild species, but landraces as well. All group chilotanum, exhibits introgression from group andigenum except clones from Southern South America near its origin, where the two groups are not highly differentiated. Moving north, we do not observe evidence for the same level of admixture back into group andigenum. This suggests that extensive history of admixture is a particular characteristic of chilotanum.

Variant calling in polyploids for population and quantitative genetics.

Advancements in genome assembly and sequencing technology have made whole genome sequence (WGS) data and reference genomes accessible to study polyploid species. Compared to popular reduced-representation sequencing approaches, the genome-wide coverage and greater marker density provided by WGS data can greatly improve our understanding of polyploid species and polyploid biology. However, biological features that make polyploid species interesting also pose challenges in read mapping, variant identification, and genotype estimation. Accounting for characteristics in variant calling like allelic dosage uncertainty, homology between subgenomes, and variance in chromosome inheritance mode can reduce errors. Here, I discuss the challenges of variant calling in polyploid WGS data and discuss where potential solutions can be integrated into a standard variant calling pipeline.

nQuack: An R package for predicting ploidal level from sequence data using site-based heterozygosity.

Premise: Traditional methods of ploidal-level estimation are tedious; using DNA sequence data for cytotype estimation is an ideal alternative. Multiple statistical approaches to leverage sequence data for ploidy inference based on site-based heterozygosity have been developed. However, these approaches may require high-coverage sequence data, use inappropriate probability distributions, or have additional statistical shortcomings that limit inference abilities. We introduce nQuack, an open-source R package that addresses the main shortcomings of current methods. Methods and Results: nQuack performs model selection for improved ploidy predictions. Here, we implement expectation maximization algorithms with normal, beta, and beta-binomial distributions. Using extensive computer simulations that account for variability in sequencing depth, as well as real data sets, we demonstrate the utility and limitations of nQuack. Conclusions: Inferring ploidy based on site-based heterozygosity alone is difficult. Even though nQuack is more accurate than similar methods, we suggest caution when relying on any site-based heterozygosity method to infer ploidy.

Assessment of Cassava Pollen Viability and Ovule Fertilizability under Red-Light, 6-Benzyl Adenine, and Silver Thiosulphate Treatments.

Understanding pollen and ovule fertility as factors influencing fruit and seed set is important in cassava breeding. Extended daylength with red light (RL) and plant growth regulators (PGRs) have been used to induce flowering and fruit set in cassava without any reference to effects on pollen viability or ovule fertilizability. This study investigated the effects of field-applied RL and PGR on pollen viability and ovule fertilizability. Panels of cassava genotypes with early or moderate flowering responses were used. RL was administered from dusk to dawn. Two PGRs, 6-benzyl adenine (BA), a cytokinin and silver thiosulphate (STS), an anti-ethylene, were applied. Pollen viability was assessed based on pollen grain diameter, in vitro stainability, in vivo germinability, ovule fertilizability, and ploidy level. Treating flowers with RL increased the pollen diameter from 145.6 in control to 148.5 µm in RL, 78.5 to 93.0% in stainability, and 52.0 to 56.9% in ovule fertilizability in treated female flowers. The fruit set also increased from 51.5 in control to 71.8% in RL-treated female flowers. The seed set followed a similar trend. The ploidy level of pollen from RL-treated flowers increased slightly and was positively correlated with pollen diameter (R2 = 0.09 *), ovule fertilization (R2 = 0.20 *), fruit set (R2 = 0.59 *), and seed set (R2 = 0.60 *). Treating flowers with PGR did not affect pollen diameter but increased stainability from 78.5% in control to 82.1%, ovule fertilizability from 42.9 to 64.9%, and fruit set from 23.2 to 51.9% in PGR-treated female flowers. Combined BA + STS application caused the highest ovule fertilizability, fruit, and seed set efficiency. These results show that RL and PGR treatments increase pollen viability and ovule fertilizability. This is important for planning pollination strategies in cassava breeding programmes.

Investigation of Sexes and Fertility Potential of Female Russian Sturgeon (Acipenser gueldenstaedtii) and Male American Paddlefish (Polyodon spathula) Hybrids.

In the present study, 10 allotriploid (3nALT) and 10 allopentaploid (5nALP) six-month-old hybrid fish and two 3nALT and four 5nALP 40-month-old hybrid fish, which resulted by crossing female Russian sturgeon Acipenser gueldenstaedtii (Brandt and Ratzeberg, 1833) and male American paddlefish Polyodon spathula (Walbaum, 1792), were investigated. It was revealed that six-month-old 3nALT and 5nALP hybrids initially had "undifferentiated" gonads, while in the 40-month-old hybrids, only testes were observed in one case of 3nALT and one case of 5nALP hybrids. The testis of 3nALT hybrids was partially developed with spermatogonia, while the testis of one 5nALP hybrid was in the second developmental stage with low spermatogonia density. We could not determine gonad differentiation in any of the cases when the hybrid individuals had the W sex chromosome. We concluded that the gonad differentiation of these interfamilial hybrids follows a similar pattern to interspecific hybrids of different ploidy parent species of the family Acipenseridae, which is consistent with the classical Haldane's rule. However, it cannot be excluded that the testis of this/these hybrid(s) may produce fertile sperm after sexual maturity, depending on additional genetic, hormonal and environmental factors, and further research is required for its evaluation.

First Gynogenesis of Vanilla planifolia for Haploid Production and Ploidy Verification Protocol.

Vanilla orchids are members of the Vanilloideae orchid subfamily, and they hold significant economic value as a spice crop in tropical regions. Despite the presence of 180 known species within this subfamily, commercial production focuses on only three species (Vanilla planifolia, V. odorata, and V. pompona) and one hybrid (V. × tahitensis), prized for their aromatic qualities and bioactive compounds. Limited modern breeding initiatives have been undertaken with vanilla orchids, although recent advancements in genomic research are shedding light on this crop's potential. The protracted breeding cycle of vanilla, coupled with increasing demand for germplasm, underscores the importance of research and breeding efforts in vanilla. This paper outlines a protocol for haploid production in V. planifolia using unfertilized ovaries in tissue culture conditions. Additionally, we present a methodology to confirm the haploid nature of putative haploid lines through stomatal size comparison, chromosome counting, and flow cytometry analysis, proving the successful development of haploid vanilla plants. These findings contribute to the advancement of breeding programs and genetic improvement strategies for the vanilla industry.

An expert opinion on rescuing atypically pronucleated human zygotes by molecular genetic fertilization checks in IVF.

IVF laboratories routinely adopt morphological pronuclear assessment at the zygote stage to identify abnormally fertilized embryos deemed unsuitable for clinical use. In essence, this is a pseudo-genetic test for ploidy motivated by the notion that biparental diploidy is required for normal human life and abnormal ploidy will lead to either failed implantation, miscarriage, or significant pregnancy complications, including molar pregnancy and chorionic carcinoma. Here, we review the literature associated with ploidy assessment of human embryos derived from zygotes displaying a pronuclear configuration other than the canonical two, and the related pregnancy outcome following transfer. We highlight that pronuclear assessment, although associated with aberrant ploidy outcomes, has a low specificity in the prediction of abnormal ploidy status in the developing embryo, while embryos deemed abnormally fertilized can yield healthy pregnancies. Therefore, this universal strategy of pronuclear assessment invariably leads to incorrect classification of over 50% of blastocysts derived from atypically pronucleated zygotes, and the systematic disposal of potentially viable embryos in IVF. To overcome this limitation of current practice, we discuss the new preimplantation genetic testing technologies that enable accurate identification of the ploidy status of preimplantation embryos and suggest a progress from morphology-based checks to molecular fertilization check as the new gold standard. This alternative molecular fertilization checking represents a possible non-incremental and controversy-free improvement to live birth rates in IVF as it adds to the pool of viable embryos available for transfer. This is especially important for the purposes of 'family building' or for poor-prognosis IVF patients where embryo numbers are often limited.

Agricultural intensification reduces selection of putative plant growth-promoting rhizobacteria in wheat.

The complex evolutionary history of wheat has shaped its associated root microbial community. However, consideration of impacts from agricultural intensification has been limited. This study investigated how endogenous (genome polyploidization) and exogenous (introduction of chemical fertilizers) factors have shaped beneficial rhizobacterial selection. We combined culture-independent and -dependent methods to analyze rhizobacterial community composition and its associated functions at the root-soil interface from a range of ancestral and modern wheat genotypes, grown with and without the addition of chemical fertilizer. In controlled pot experiments, fertilization and soil compartment (rhizosphere, rhizoplane) were the dominant factors shaping rhizobacterial community composition, whereas the expansion of the wheat genome from diploid to allopolyploid caused the next greatest variation. Rhizoplane-derived culturable bacterial collections tested for plant growth-promoting (PGP) traits revealed that fertilization reduced the abundance of putative plant growth-promoting rhizobacteria in allopolyploid wheats but not in wild wheat progenitors. Taxonomic classification of these isolates showed that these differences were largely driven by reduced selection of beneficial root bacteria representative of the Bacteroidota phylum in allopolyploid wheats. Furthermore, the complexity of supported beneficial bacterial populations in hexaploid wheats was greatly reduced in comparison to diploid wild wheats. We therefore propose that the selection of root-associated bacterial genera with PGP functions may be impaired by crop domestication in a fertilizer-dependent manner, a potentially crucial finding to direct future plant breeding programs to improve crop production systems in a changing environment.

Beyond black-box models: explainable AI for embryo ploidy prediction and patient-centric consultation.

PURPOSE: To determine if an explainable artificial intelligence (XAI) model enhances the accuracy and transparency of predicting embryo ploidy status based on embryonic characteristics and clinical data. METHODS: This retrospective study utilized a dataset of 1908 blastocyst embryos. The dataset includes ploidy status, morphokinetic features, morphology grades, and 11 clinical variables. Six machine learning (ML) models including Random Forest (RF), Linear Discriminant Analysis (LDA), Logistic Regression (LR), Support Vector Machine (SVM), AdaBoost (ADA), and Light Gradient-Boosting Machine (LGBM) were trained to predict ploidy status probabilities across three distinct datasets: high-grade embryos (HGE, n = 1107), low-grade embryos (LGE, n = 364), and all-grade embryos (AGE, n = 1471). The model's performance was interpreted using XAI, including SHapley Additive exPlanations (SHAP) and Local Interpretable Model-agnostic Explanations (LIME) techniques. RESULTS: The mean maternal age was 38.5 ± 3.85 years. The Random Forest (RF) model exhibited superior performance compared to the other five ML models, achieving an accuracy of 0.749 and an AUC of 0.808 for AGE. In the external test set, the RF model achieved an accuracy of 0.714 and an AUC of 0.750 (95% CI, 0.702-0.796). SHAP's feature impact analysis highlighted that maternal age, paternal age, time to blastocyst (tB), and day 5 morphology grade significantly impacted the predictive model. In addition, LIME offered specific case-ploidy prediction probabilities, revealing the model's assigned values for each variable within a finite range. CONCLUSION: The model highlights the potential of using XAI algorithms to enhance ploidy prediction, optimize embryo selection as patient-centric consultation, and provides reliability and transparent insights into the decision-making process.

Multiple collapses of blastocysts after full blastocyst formation is an independent risk factor for aneuploidy - a study based on AI and manual validation.

BACKGROUND: The occurrence of blastocyst collapse may become an indicator of preimplantation embryo quality assessment. It has been reported that collapsing blastocysts can lead to higher rates of aneuploidy and poorer clinical outcomes, but more large-scale studies are needed to explore this relationship. This study explored the characteristics of blastocyst collapse identified and quantified by artificial intelligence and explored the associations between blastocyst collapse and embryo ploidy, morphological quality, and clinical outcomes. METHODS: This observational study included data from 3288 biopsied blastocysts in 1071 time-lapse preimplantation genetic testing cycles performed between January 2019 and February 2023 at a single academic fertility center. All transferred blastocysts are euploid blastocysts. The artificial intelligence recognized blastocyst collapse in time-lapse microscopy videos and then registered the collapsing times, and the start time, the recovery duration, the shrinkage percentage of each collapse. The effects of blastocyst collapse and embryo ploidy, pregnancy, live birth, miscarriage, and embryo quality were studied using available data from 1196 euploid embryos and 1300 aneuploid embryos. RESULTS: 5.6% of blastocysts collapsed at least once only before the full blastocyst formation (tB), 19.4% collapsed at least once only after tB, and 3.1% collapsed both before and after tB. Multiple collapses of blastocysts after tB (times ≥ 2) are associated with higher aneuploid rates (54.6%, P > 0.05; 70.5%, P < 0.001; 72.5%, P = 0.004; and 71.4%, P = 0.049 in blastocysts collapsed 1, 2, 3 or ≥ 4 times), which remained significant after adjustment for confounders (OR = 2.597, 95% CI 1.464-4.607, P = 0.001). Analysis of the aneuploid embryos showed a higher ratio of collapses and multiple collapses after tB in monosomies and embryos with subchromosomal deletion of segmental nature (P < 0.001). Blastocyst collapse was associated with delayed embryonic development and declined blastocyst quality. There is no significant difference in pregnancy and live birth rates between collapsing and non-collapsing blastocysts. CONCLUSIONS: Blastocyst collapse is common during blastocyst development. This study underlined that multiple blastocyst collapses after tB may be an independent risk factor for aneuploidy which should be taken into account by clinicians and embryologists when selecting blastocysts for transfer.

Ploidy variation induces butterfly effect on chromatin topology in wheat.

Polyploidy is a prominent driver of plant diversification, accompanied with dramatic chromosomal rearrangement and epigenetic changes that affect gene expression. How chromatin interactions within and between subgenomes adapt to ploidy transition remains poorly understood. We generate open chromatin interaction maps for natural hexaploid wheat (AABBDD), extracted tetraploid wheat (AABB), diploid wheat progenitor Aegilops tauschii (DD) and resynthesized hexaploid wheat (RHW, AABBDD). Thousands of intra- and interchromosomal loops are de novo established or disappeared in AB subgenomes after separation of D subgenome, in which 37-95% of novel loops are lost again in RHW after merger of D genome. Interestingly, more than half of novel loops are formed by cascade reactions that are triggered by disruption of chromatin interaction between AB and D subgenomes. The interaction repressed genes in RHW relative to DD are expression suppressed, resulting in more balanced expression of the three homoeologs in RHW. The interaction levels of cascade anchors are decreased step-by-step. Leading single nucleotide polymorphisms of yield- and plant architecture-related quantitative trait locus are significantly enriched in cascade anchors. The expression of 116 genes interacted with these anchors are significantly correlated with the corresponding traits. Our findings reveal trans-regulation of intrachromosomal loops by interchromosomal interactions during genome merger and separation in polyploid species.

The haplotype-resolved Prymnesium parvum (type B) microalga genome reveals the genetic basis of its fish-killing toxins.

The catastrophic loss of aquatic life in the Central European Oder River in 2022, caused by a toxic bloom of the haptophyte microalga Prymnesium parvum (in a wide sense, s.l.), underscores the need to improve our understanding of the genomic basis of the toxin. Previous morphological, phylogenetic, and genomic studies have revealed cryptic diversity within P. parvum s.l. and uncovered three clade-specific (types A, B, and C) prymnesin toxins. Here, we used state-of-the-art long-read sequencing and assembled the first haplotype-resolved diploid genome of a P. parvum type B from the strain responsible for the Oder disaster. Comparative analyses with type A genomes uncovered a genome-size expansion driven by repetitive elements in type B. We also found conserved synteny but divergent evolution in several polyketide synthase (PKS) genes, which are known to underlie toxin production in combination with environmental cues. We identified an approximately 20-kbp deletion in the largest PKS gene of type B that we link to differences in the chemical structure of types A and B prymnesins. Flow cytometry and electron microscopy analyses confirmed diploidy in the Oder River strain and revealed differences to closely related strains in both ploidy and morphology. Our results provide unprecedented resolution of strain diversity in P. parvum s.l. and a better understanding of the genomic basis of toxin variability in haptophytes. The reference-quality genome will enable us to better understand changes in microbial diversity in the face of increasing environmental pressures and provides a basis for strain-level monitoring of invasive Prymnesium in the future.

Leveraging federated learning for boosting data privacy and performance in IVF embryo selection.

PURPOSE: To study the effectiveness of federated learning in in vitro fertilization on embryo evaluation tasks. METHODS: This is a retrospective cohort analysis. Two datasets were used in this study. The ploidy status dataset consisted of 10,065 embryo records, 3760 treatments, and 2479 infertile couples from 5 hospitals. The clinical pregnancy dataset consisted of 4495 embryo records, 4495 treatments, and 3704 infertile couples from 4 hospitals. Federated learning and the gradient boosting decision tree algorithm were utilized for modeling. RESULTS: On the ploidy status dataset, the areas under the receiver operating characteristic curves of our model trained with federated learning were 71.78%, 73.10%, 69.39%, 69.72%, and 73.46% for 5 hospitals respectively, showing an average increase of 2.5% compared to those of our model trained without federated learning. On the clinical pregnancy dataset, the areas under the receiver operating characteristic curves of our model trained with federated learning were 72.03%, 56.77%, 61.63%, and 58.58% for 4 hospitals respectively, showing an average increase of 3.08%. CONCLUSIONS: Federated learning can improve data privacy and data security and meanwhile improve the performance of embryo selection tasks by leveraging data from multiple sources. This study demonstrates the effectiveness of federated learning in embryo evaluation, and the results show the promise for future application.